1. Field of the Invention
The present invention relates to a particular image area partitioning apparatus and method, and a program for causing a computer to perform particular image area partitioning processing, and more specifically, to an apparatus for and a method of suitably partitioning off a particular image portion included in an image represented by image data (determining, demarcating or judging a boundary between a particular image portion and the other portion, or detecting or extracting the particular image portion).
2. Description of the Background Art
An image represented by digital image data is displayed on a display screen of a display device, and is printed on printing paper by a printer. The image represented by the digital image data is visibly displayed on the display screen or the printing paper. In order to reproduce the image displayed on the display screen or the printing paper more beautifully (or faithfully), the digital image data is subjected to various types of correction processing such as white balance correction and gamma correction in a digital camera, a printer, a personal computer, etc.
The image data may, in some cases, be subjected to correction processing by paying attention to a particular image portion included in the image. When the image includes the face of a character (person), an image portion of the face of the character is used as an object to perform correction processing such as white balance correction and gamma correction such that the face of the character is more beautifully (faithfully) represented.
In order to subject the image data representing the particular image portion included in the image (e.g., the image portion of the face of the character) to correction processing, the particular image portion must be detected (extracted, cut out, bounded, partitioned off, demarcated) from the entire image. In JP-A-2002-203239, a skin candidate area is first detected, and main face features (eyes, eyebrows, hair, nose, and mouth) in the detected skin candidate area are then detected, to detect a face image included in the image. However, face images included in all images are not constant in direction or size. In a detecting method based on the face features (eyes, eyebrows, hair, nose, and mouth), detection may fail. As to detection of the skin candidate area, when the color of a background is close to a skin color, detection of the area (boundary) may fail.